You sir may be on to something. The first thing I noticed when I popped the intake off is how much offset the cam has compared to the lifters. I know the lifters don't run on the center of the lobes but, this seams extreme to me. The other thing was the end of the oil pump drive rod has some scoring on it so, I wonder if the cam is so far deep in the block that it's pushing on the distributor so hard that the drive rod was actually rubbing the block where it slides down to the the oil pump. The drive rod also has a couple gouges where the distributor shaft key locks into the rod maybe, as if the cam is so deep he had a hell of a time getting distributor in and he laid the wood to it. I also want to add that the first few times we started it the noise was not immediate, the engine would run 5 to 10 seconds then the noise would come in.
View attachment 1716206522
View attachment 1716206523
